The big picture Of Immunization

After receiving their individual vaccinations against measles, children wave their campaign cards showing that they have been immunized.

Immunization is one of the most successful and cost-effective public health interventions. According to the latest data, in 2010, global efforts to immunize children with vaccines against life-threatening diseases set a record high, reaching 109 million children and averting more than two million deaths along with countless episodes of illness and disability annually.

However, despite significant gains in recent years, some 19.3 million children (almost 20% of children born each year) are not immunized, exposing them to disabilities or premature death. Among immunized children, some 68% live in the 10 countries with the largest populations and the weakest immunization structures in the world.

Immunization has the potential to boost a country’s growth. Many analyses weighing the costs versus the benefits of vaccination have shown positive economic impact. What’s more, the infrastructure, management and acceptability of immunization programmes offer a platform to deliver other integrated health and nutrition interventions.

Vaccines work by introducing into a person’s immune system a harmless form of a bacterium, toxin or virus that a healthy person’s body recognizes as unusual and responds by devising a defense (immunity) against it.

The most commonly applied global standard of routine immunization coverage is reflected in an individual’s receipt of three doses of DTP (diphtheria, tetanus and pertussis) vaccine, or DTP3. The most recent estimates show a continuing positive trend in global DTP3 coverage, which was received by 85% of children under one year of age.

Disparities in immunization coverage exist within and among the world’s regions and countries. While DTP3 coverage is 96% in the industrialized countries, none of the regions in South Asia and sub-Saharan Africa have been able to attain such high coverage, leaving large unimmunizatied populations in the least developed countries. To make matters worse, an inequity of coverage prevails within many countries, especially developing countries.

UNICEF and its partner organizations are responding to the challenge with a global push to ensure that the hardest children to reach – most of them in Africa and Asia – are immunized. Major initiatives are underway to accelerate the development and deployment of new and underused vaccines, for example hepatitis B (Hep B) and Haemophilus influenzae type b (Hib) vaccine. The number of countries using Hep B vaccine has increased from 107 in 2000 to 179 in 2010 and for the Hib vaccine, has increased from 29 in 1997 to 166 in 2010.

Significant progress has been made to reduce mortality and morbidity due to vaccine preventable diseases such as polio, measles and maternal and neonatal tetanus through supplementary immunization activities or campaigns, in addition to routine vaccination programmes. These campaigns provide valuable opportunities to reach children in older age groups compared to routine vaccination and to introduce other high-impact life-saving interventions such as vitamin A tablets, insecticide treated bed nets and de-worming tablets.

Achievements aside, there are daunting challenges in vaccinating all target children, not least of which is rising cost. Providing traditional and new vaccines (such as HepB and Hib) can now cost as much as $20 to $40 per child. Other obstacles to higher coverage include non-availability of sustainable resources, poor management and logistics systems, inequity in services, and a lack of community engagement.